Iron (Fe) is a trace element that plays an essential role for oxygen transport in the body, and is an important constituent of hemoglobin, myoglobin, cytochrome, iron/sulfur protein and biomolecular structures. The total amount of iron in the body is about 3 to 4 g, 60 to 65% of which is bound to hemoglobin in circulating erythrocytes, and the remaining 30 to 35% is present as storage iron (ferritin). Iron is also present in the form of tissue iron and serum iron (transferrin), and furthermore, there is a small amount of iron in myoglobin of the muscles.
Iron is not synthesized in the body and thus must be acquired entirely through intake, and exists in two types, heme iron and nonheme iron. Heme iron is an iron complex having a moiety having the same structure as the heme of hemoglobin in the body, and nonheme iron is an iron complex not having a moiety having the same structure as the heme of hemoglobin. These two types of iron may be used as iron supplements (iron supplementary compound), and the bioavailability of heme iron is known to be much higher than that of nonheme iron. Also, the absorption of heme iron in the body is not affected by other dietary factors. Moreover, heme iron has the advantage of not causing various side effects (constipation, gastrointestinal disorders, etc.) that have been reported for nonheme iron.
Generally, heme iron is manufactured from blood of slaughtered animal, such as porcine blood. The heme iron is prepared from slaughterhouse blood by a manner in which hemoglobin is first separated from the slaughterhouse blood and then heme iron is isolated from the separated hemoglobin. The separation of heme iron from hemoglobin may be performed through a method of using an alcohol and an imidazole derivative (Lindroos, U.S. Pat. No. 4,431,581), a method of adding amino acids thereto (Ingberg, et. al., U.S. Pat. No. 5,008,388), a method of performing decomposition at a high temperature using a highly concentrated organic acid (Liu, et. al., J. Agric. Food Chem., 44, 2957, 1996), a method of using a protease, and the like.
Heme iron thus prepared has many problems that are not present in nonheme iron, such as the risk of infection by animal-derived infection sources, livestock growth hormone contamination, and residual antibiotics. Moreover, the preparation of heme iron as described above involves the production of heme iron from blood obtained from the slaughter of animals such as pigs, which is forbidden by Islam, and thus the heme iron above prepared does not conform to halal regulations, undesirably obstructing the use thereof as an iron supplement by Muslims.
Therefore, it is necessary to develop a method of preparing heme iron not derived from porcine blood.